I have always used and been a fan of 2.2. It makes sense to use what most others use, imo. When you choose colours for a site you know that most people will see similar colours.
With a gamma of 1.8 I found that on other machines using 2.2, light colours I chose tended to look white and dark colours looked black.
With a gamma of 1.8 I found that on other machines using 2.2, light colours I chose tended to look white and dark colours looked black.